Recoil and buffer spring assembly for automatic fire arms



E- HEPPERLE Dec. 6, 1960 RECOIL AND BUFFER SPRING ASSEMBLY FOR AUTOMATIC FIRE ARMS Filed Dec. 18, 1957 ERWIN HEPPERLE INVENTOR RECOIL AND BUFFER SPRING ASSEMBLY FOR AUTOMATIC FIRE ARMS Erwin Hepperle, Eichelacker of Dietlikon-Zurich, Switzerland, assignor to Machine Tool Works ()erlikon, Administration Company, Zurich-Oerlikon, Switzerland, a Swiss company Filed Dec. 18, 1957, Ser. No. 703,537

Claims priority, application Switzerland Dec. 21, 1956 1 Claim. (or. 89-44 The present invention relates to automatic fire arms are more particularly to recoil spring arrangements thereof. For reliability in operation and accuracy in firing one has endeavoured to attain by suitable measures a uniform and jerk-free course of the recoil movements of automatic recoiling guns, in such a manner that these movements repeat themselves uniformly after each shot and accordingly each recoil starts under equal conditions. It is known that this can be achieved by the combined use of a recoil spring and a hydraulic brake acting on the gun when the latter is moving forward.

This solution is however only partly satisfactory since the hydraulic brakes are fraught in part with serious disadvantages impairing their faultless function, such as sensitivity to temperature and to adjustment, occurrence of leakage losses, which require reliable servicing, and moreover their comparatively high weight, which is particularly disadvantageous for fire arms on board combat aircraft.

The present invention has the principal object of attaining a uniform course free from jerks of the recoiland advance-movements thereof. It is another object of the present invention to provide a recoil spring mechanism which is light in weight, insensitive to variations in temperature and requiring little servicing, if any.

With these and other objects in view I provide an automatic fire arm, comprising in combination: a gun structure, a gun mounted reciprocatably in the said structure and having a barrel and a plurality of cartridge chambers consecutively brought in alignment with the said barrel, at least two friction ring springs interposed preloaded between the said structure and the said gun and having a steeper spring characteristic upon compression than upon expansion, one of the said springs cushioning the recoil of the said gun as a recoil spring and another cushioning the advance of said gun as a buffer spring, the pre-loading of the said springs being so dimensioned, that during the greater part of the recoil and advance of the said gun the said friction ring springs impart opposite spring forces to the said gun.

These and other features and objects of my present invention will be clearly understood from the following description of a preferred embodiment thereof, given by way of example with reference to the accompanying drawing, in which:

Fig. l is a diagrammatic illustration of a revolver gun sprung according to the invention.

Fig. 2 shows the arrangement of the components of the revolver gun according to Fig. l forming the recoil spring arrangement, on a larger scale.

Fig. 3 is a working graph of the recoil spring arrangement according to Figs. 1 and 2.

As illustrated in Fig. 1, the barrel 1 is inserted by means of a bayonet joint in the casing 2 of the gun 19, wherein also the revolver drum 3 provided with the cartridge chamber is mounted rotatably. A cartridge 4, which is contained in a cartridge chamber positioned behind the 2,952,935 Patented Dec. 6, 1960 barrel 1, bears, when fired, on the wall 5 of the casing 2 and transmits the recoil forces on to the same. Through a bore 6 gas is passed from the barrel to a piston 7, which in a known manner operates the carriage 8 setting the drum in rotation.

According to Fig. 2 the gas tapping piece 10 is fixedly clamped to the casing 2 by means of nut 11. A friction ring spring 12 abuts on the one hand this gas tapping piece 10, and on the other hand a flange 14 of a cylinder 13. A ring flange 15 of this cylinder is fixedly connected by screw bolts 16 to the structure 17, for example of an aircraft, the same as the guides 9 illustrated in Fig. 1, wherein the weapon is mounted. .The friction ring spring 12 acts on the casing 2 in the direction of the shot, while a second friction ring spring 18, which is arranged co-axially to the first mentioned one and likewise bears on the cylinder 13 and on the casing 2, acts on the latter in the opposite direction. The casing comprises the casing part 2 and the gas tapping piece 10.

The cooperation of these two friction ring springs dur-. ing the recoil and subsequent forward movement of the gun according to Fig. l is illustrated by way of example in the graph represented in Fig. 3 wherein the spring forces are plotted as ordinates Y over the spring paths forming the abscissae X. The arrow S indicates the direction of the shot. The characteristic feature of the resilient elements known under the term of friction spring ring is known to be the difference of the spring forces when compressing and expanding the spring. In Fig. 3 the line AB indicates the force of the spring 12 during the recoil of the gun, and the line C-A the force of the same spring during the forward movement thereof. The line FD indicates the course of the force of the spring 18 during the recoil of the gun, and the line DE the course of the force of this spring during the forward movement thereof. By a and 2 two springing positions are denoted which mark for example two abutments between which the gun can oscillate to-and-fro.

When the gun recoils after a shot, for example from the position illustrated in Fig. 2, in which the springs are in the springing position marked 0 in Fig. 3, it is opposed by the force resulting from the co-operation of the two springs according to the line GHJ until its rear reversal point is reached at the spring position 1; in the subsequent course the gun is initially accelerated by a force, which is small as compared with that acting during the rec-oil and which decreases to zero value along the line KLM, and is then braked smoothly and without jerk by a force increasing according to the line M-N. The gun advancing at a low rate will come to a standstill either under the action of the recoil forces occurring at the next shot, for example at the springing position denoted d and then recoil again, or will be braked to a standstill at prolonged firing intervals in the springing position 0, whereafter it remains in this position until it is thrown back again by the next recoil.

In general, a gun having a recoil spring arrangement according to the present invention when coming to a standstill within the springing range between I) and e will remain in this condition till the impact of the high recoil forces. Movement of the gun in the direction of firing is impossible, since the force of the spring 12 acting in this direction according to the line C--A is smaller in this springing range than the force of the spring 18 opposed to it according to the line DE, and likewise movement opposite the direction of firing is impossible since the force of the spring 18 according to the line FD in this springing range between b and e is also smaller than the force according to the line AB of the spring 12 opposing the same.

The recoil spring arrangement according to the present invention completely replaces the combination of spring plus hydraulic brake in that therewith likewise a jerkfree and regular course of the recoil movements as re quired for the faultless functioning of a gun are attained as proved by tests.

There is no departing from the invention when for example the friction ring springs are 'ar ranged onebehind the other, or when instead of two friction ring springs several thereof are used for constituting the'recoil spring arrangements, provided the same act'in the sense of the foregoing specification and of the graph illustrated in Fig. 3.

What I claim as my invention and desire to secure by Letters Patent, is:

An automatic firearm, comprising in combination a support structure, a gun mounted reciprocatably from a starting position to a rear reversal point in said structure, a first and a second friction ring spring interposed between said structure and said gun, said gun comprising a barrel fixedly connected with a gas tapping piece and a casing,

a cylinder with a flange arranged coaxially to said barrel and fixedly connected with said structure, said first friction ring spring being arranged coaxially to said barrel on the inside of said cylinder and abutting on the one hand said gas tapping piece and on the other hand said flange of said cylinder, said second friction ring spring being arranged coaxially to said barrel on the outside of said cylinder and acting between said cylinder and said casing, said first and second friction ring springs imparting at least in said starting position simultaneously opposite spring forces to said gun.

References Cited in the file of this patent FOREIGN PATENTS 695,594 Germany Aug. 28, 1940 717,050 Germany .v. Feb. 4, 1942 559,586 Great Britain Feb. 25, 1944 1,041,139 7 France May 27, 1953 

